Low frequency fields generate electric fields and currents in the human body. As a consequence nerve and muscle cells can be stimulated. The limit values set out in the 26th German Federal Immission Protection Ordinance (26. BImSchV) protect against the proven health-related effects of low frequency electric and magnetic fields. No health risks have been demonstrated for static electric and magnetic fields occurring in usual exposure situations that arise from direct current power lines.

In the debate on grid expansion and high-voltage power lines, the discharge effects in the immediate vicinity of the lines ("corona effects") and their impact on animals and plants are of major relevance.

Strong electric and magnetic fields exceeding the existing limit values can lead to health impairments. Whether low-frequency fields could have any further health effects, apart from these established effects, - possibly below the limit values, too - is currently being researched.